In the fields of a coating and an adhesive, various thermosetting resin compositions are used. In many of such thermosetting resin compositions, a resin having two or more hydroxyl groups is used in combination with a curing agent and the resin is cured by a crosslinking reaction between the curing agent and the hydroxyl group.
As the curing agent, melamine resins, epoxy compounds, and polyisocyanate compounds are used. These curing agents are widely and generally used because the curing agents nave a good thermal reactivity and cured resins obtained by using the curing agent have superior characteristics. However, the melamine resin is presumed as the cause of sick house syndrome because it generates formaldehyde, so that it has been restricted in uses. In addition, if it is used in a coating, a problem in acid resistance is known to occur because of its chemical structure.
Epoxy compounds are said to have a low storage stability and a high curing temperature, though they are high in curability and coating film properties. Polyisocyanate curing system is said to be high in cost and show a narrow range of design though they are high in curability and coating film properties. On the other hand, the curing system of the present invention has a high curability and a wide range of design to develop the desired coating film properties, and has a high storage stability and does not by-produce harmful substances.
Patent document 1 discloses a powder coating using a transesterification reaction as a curing reaction. However, only the use of a powder coating is disclosed, and the use of general solvent-type or water-borne compositions is not disclosed.
Further, if used as a coating and an adhesive agent, water resistance is required but this point is not disclosed. Actually, a solvent-type coating was prepared by the method of patent document 1 and evaluated so that a sufficient water resistance or crosslinking reactivity cannot be achieved. That is, a specific method for applying the composition to a coating and an adhesive agent in the form of a solvent-type or a water-borne composition is not disclosed in patent document 1.
Patent document 2 discloses a coating using a transesterification reaction as a curing reaction. In this document, a detailed composition of the resin to be used is not restricted, and a composition which can be suitably used for a curable composition through a transesterification reaction is not identified.